Predicting a call is jumping a call and that always leads to mistakes.

Secondly, tennis commentators though the years have proven beyond a shadow of a doubt, evidenced by their own words that they understand next to nothing about on court officiating, line calling, chair procedures or the rules of tennis...and this especially applies to the former players turned commentators.

Click to expand...

Maybe the commentators mean that the official mentally anticipates where the ball will go based on the speed and spin on the ball. I think they make the call after they have seen it bounce.